Identifiable material and method of making the same



Patented Nov. 1, 1932 I mum/teammate mpnmmw maa KUHL, or CUMBERLAND, MARYLAND,

'nssienon r cnLANEsn CORPORATION on Armen an, A o-onr'onarron or DELAWARE I nnnrirrannnri'arrnnmr. AND METHOD or MnKING'THE S E r, NoDrawing. v

This invention relates tothe preparation of artificial yarns 'or' other materials which yarns or other materials have therein a foreign. substance that maybe readily identifiecl', especially when present in small quantities. V a

An object of our invention is to render artificial yarn, films, plastic masses or coating compositions readily identiiiable by the addition to the solution of which they are formed, or to the yarn or other articles after their formation, of a compound of a metal that can be readily identified. Other objects of our invention will appear from the following detailed description.

Oftenit is desirable to have artificial yarns, films, plastic masses or coating compositions prepared so that they may be readily identified as to the nature of the materials employed in their manufacture, the method of preparing them and the source of manufacture. When only small amounts of the yarn or other articles are available, it is diflicult to identify the same by ordinary methods of chemical or physical analysis. We have found, however, that if a small amount of readily detectable compounds are added to the yarns, they may be easily identified.

In one form of our invention, we prepare artificial yarns of any nature by adding either to the solution from which they are spun, or to the yarns after they are formed, a small amount of a compound that does not occur in the substances from which the yarn is prepared, but which may be readily detected either by physical tests or by chemical tests. Likewise, when films, plastic masses or coating compositions are to be treated in accordance with our invention, such foreign compound may be added to the solutions from which they are formed.

The yarn that forms the subject of this invention may be made of any suitable cellulosic material or its derivatives. Thus the yarn may be made of organic derivatives of cellulose which include organic esters of cellulose or organic ethers of cellulose. Examples of organic esters of cellulose are cellulose acetate, cellulose formate, cellulose 50 propionate and cellulose butyrate; while ex- Application filedifuly 27,1928. Serial no. 295,339.

amples of cellulose ethers areethyl cellulose, methyl cellulose and'benzyl cellulose. The yarns are prepared from these organic derivatives of cellulose by dissolving the same in a suitable volatile solvent, and extruding such solution through the orifices of 'spinerettes, either into a heated evaporative atmosphere as in dry spinning or into a precipitating bath as in wet spinning. This inventi'on, however, is not restricted to yarn'made' of organic derivatives of cellulose, but also includes yarns of the reconstituted cellulose type such as are made by the viscose, cupramonnium or the Chardonet process.

The foreign substance addedmay beany 5. suitable compound thatis readily detectable. As an example of a compound that may be detected by physical means, strontium salts, particularly strontium chloride, may be mentioned. The yarn containing strontium salts may be tested either by the flame test, or in the spectroscope for the characteristic strontium spectrum. As an example of a compound that may be added to the yarn and which may be readily detected by chemical analysis,inickel salts, and particularlynickel chloride, is mentioned. The nickel comounds give a very delicate reaction with dimethyl glyoxime (CH QC (N OH) a The proportions of the detectable material so that may be added to the yarn may vary from V 10 to 40 or more parts of the compound toone million parts of the yarn. Generally we prefer to add as small an amount of the compound. as possible because of regard to the cost and other considerations. However, we prefer to add a sufiicient amount of this compound so that it may bedetected with samples of yarn as small as one gram. Thus we find that when we employa water soluble salt such as nickel chloride (NiCl .6H O), 40 parts of this material per million parts of the yarn produce aproduct that is not substantially affected by subsequent washings, dyeings, scourings and the like.

4 Theyarn, when prepared as above,'may be readily identified. A convenient. method of making the analysis of such yarn when it contains a strontium compound is to reduce the same to anash and then to test the ash either 190 55 masses containing ence of sulphuric acid, so volatile chloride to the less tion but without being I in a flame or by the 'by heated air. The filaments aid of a spectroscope. For the testing of yarn containing a nickel salt, the yarn is ashed and the nickel contained therein is dissolved in the form of a salt in a small quantity of slightly alkaline water.

This solution is then treated with an alcoholic solution of dimethyl glyoxime. Thenickel combines with the dimethyl glyoXimeto fornr a characteristic red crystalline precipitate. Of course it is understood that if volatile-- 'Sa-ltS,'Sl1Cl1 as nickel chloride, are employed,

it is pr ferable to ash the same in the presas to convert'th'e volatile sulphate. While we have specifically cited compounds ,ofnickel and stronti-mn, it is to be understood that compounds of other metals may be employed. The reason that these metals have been specifically named is that they give pronounced physical or chemical tests and that they'do not occur in theingredients commonly, employed for making artificial yarns. Furthermore, nickelis very resistant to the acids, alkalies, e.tc., employed in the manufacture and treatment of textile materials, andtherefore yarns donot ordinarily become contaminated with nickel that may be used in apparatusemployed for producing such yarn. 5 In order-further to illustrate our invenlimitedthereto the followingspecific example is given.

Example I p A'spinning charge is made by dissolving one part of anacetone soluble cellulose acetate 'having an acetyl value of 54: to 55% in 3 parts by weight of acetone. Tothis solution is added an aqueous solution of crystalline nickel chloride in such amounts that there are present 'parts of nickel per million parts of cellulose acetate. The so lution is then spun through the orifices of a spinerette into the metier of a dry spinning machine, wherein the acetone is evaporated thus formed are drawn, twisted into yarn and wound into packages. The yarn thusmade'gives. the, characteristic nickel reaction with dimethyl glyoxime when treated as above set forth.

Although this invention has been described specifically in connection with the identification of yarns, it is equally applicable in the preparation of films, lacquers. or plastic derivatives, .of cellulose such as cellulose nitrate or the organic derivatives mentioned above. 'These films, plastic masses and coating compositions will also contain low, medium, and/or high boiling solvent-and plastifiers as is well understood in the art. I H

It is to be understood that the foregoing detailed description is given merely by way ofillustration and that manyvariations may ric or film are be made thereinwithout departing from the spirit of this invention.

The term foreign substance as used in the claims is to be interpreted as meaning substances which are not necessary for yarn, fabric or film formatio n.- Substances which normally are not %present in the yarn, fabthus included in this term.

Having described our invention what we claim anddesire to secure by Letters Patentis: Y

1. Artificial silk containing 10 to parts of a readily identifiable metal compound per one million pa-rtsj ofthe silk. g

2. Organic derivative of cellulose artificial silk containing, 10: tov .410v parts .of' a readily identifiable metal compound per one million parts of the silk.

3. Cellulose acetate artificial. silk tones mg l0, to 40 parts-of areadily identifiable mlical compound per one million parts of the 4. Cellulose acetateartificialsilk containing '10 to 40.,parts of strontium chloride per one million parts of silk. 1 ,5. Cellulose acetate artificialsilk containng 10 to 0 parts of nickel chloride per one million partsiofsilk z n testimony whereof,we have hereunto subscribed our names. I

WILLIAM WHITEHEAD. .HENR-Y WALTER vKUHL. 

